Red Seal Truck and Transport Mechanic Practice Exam

Explain the difference between a hydraulic brake system and an air brake system.

1. A hydraulic brake system uses brake fluid to create pressure, while an air brake system uses compressed air

2. Hydraulic brakes are manual, while air brakes are automatic

3. Air brakes are used exclusively in light vehicles, while hydraulic brakes are for heavy vehicles

4. Hydraulic brake systems are more fuel-efficient than air brake systems

The correct answer is: A hydraulic brake system uses brake fluid to create pressure, while an air brake system uses compressed air

A hydraulic brake system operates by utilizing brake fluid to generate pressure, which activates the braking mechanism. When the driver presses the brake pedal, the force is transferred through the brake fluid, allowing the brakes to engage smoothly and effectively. This system is commonly found in many passenger vehicles due to its simplicity, responsiveness, and compact design. On the other hand, an air brake system relies on compressed air to function. This system is predominantly used in large vehicles like trucks and buses because it can provide more robust stopping power necessary for high-mass vehicles. When the driver applies the brakes, air from a compressor fills the brake chambers, pushing the brake shoes against the drums or applying pressure to the disc brakes. Understanding the fundamental differences between these two systems is crucial, as their operation and applications vary significantly. The hydraulic system is more suited for lighter vehicles, whereas air brake systems are essential for ensuring safety and performance in larger, heavier vehicles.